Telephone system.



LAUSEN.

.TELEPHONE SYSTEM. APPLICATION ULEB JUL? 24. 1503.

H. Plv C VPatented Aug. 13, 1912.

f UNITED STATES PATENT OF'ltlllCEs HENRY P. GLAUSEN, OF CHCAGO,ILLINOIS, ASSIGN 01%,' BY MESNE ASSIGNMENTS, TO

STROISBERG-CAELSON TFLEPHGNE MANUFACTURING NEW YORK, A CIRPORA?r 'CON 0FNEW YORK.

COMPANY, OF ROCHESTER,

TELEPHONE SYSTEM.

Specification of Letters Patent.

Application filed July 24, 1903. Serial No. 166,795.

To all whom it may concern:

Be it known' that I, HENRY P. CLAUsEN, a citizen of the United States ofAmerica, and resident of Chicago, Cool( Improvement in TelephoneSystems, of which the followingis a specification.

My invention relates to telephone systems of that type in which all otthe current', both for signaling and talking purposes, Yis supplied froma common battery or centralized source of current supply located at theeX- change or central station. f l

It also relates, more particularly, to telephone systems of thatcharacter in which complete metallic line connection is. em-

ployed between the sub-stations and the eX- In systems of.

change -or central station. this type it .is also usually the practiceto employ line lamp signals for enabling` the subscribers to call-in andattract the attention of the operators, and to also employ supervisoryor clearing-out signals whereby the subscribers may signal for adisconnection. These lampv signals are usually mounted on theswitchboard and are preferably controlled by line and supervisoryrrelays. lith this arrangement, the line lamp signals respond when thesubscribers call-in by removiugtheir receivers from the switch hooks,and the supervisory signals respond when the subscribers hang` up orreplace tlieirreceivers after having finished their conversation. I

Generally stated7 the object ot my invention is the provision 'ot animproved and highly etlicicnt tclephoiu` system ot' the foregoingcharacter.

A special object is the provision of an improved circuit arrangement.whereby only two wires or conductors ,are necessary for each springjack with which the different lines are connected at the switchboard,and also tor each cord circuit by which connection is establisucdbetween the diliercnt lines. v

\nothcr object is to provide an improved construction ot line signalapparatus-that is to say. an improved construction of that portion otthe apparatus by which the subscribers call-in and attract the attentionot thtx operators.

lt is also an object to provide certain dcails and tentures ofimprovement tending` county, Illi-` nois, have invented a certain new'and useful to increase the general eliiciency and serviceability of acommon battery telephone system of this particular character. i

To the foregoing and other useful ends, my invention consists in mattershereinafter set forth and claimed.

he accompanying drawing is a diagram illustratin a common batterytelephone system embot ying the principles ot' my invention, only twosub-stations ani one operators cord circuit being shown. ,it beingunderstood, however, that the system may involve as many sub-stations asthe size and growth ofv the exchange demands, and as many operators cordcircuits as are necessary in order to enable the roperators to establishthe connections with facility and promptness.

As thus illustrated, my improved com )n battery telephone systemcomprises .ibstations A and B, the former connected by two parallellimbs or line conductors with a spring jaclr C, and the latter beinglikewise connected with a spring jack D, the two jacks being located onthe switch-boart'l at the exchange or central station. kThe system alsoinvolves an operators cor'd circuit E, provided with answering andcalling' plugs e and c1, and thus adapted tur establishing connectionbetween the l aid lines. A line signal F is associated wila the jack C,whereby subscriber A may attract the :utcntion of the operator when hedesires to talk with some other subscriber. ln a similar manner and tora similar purpose. a` line lamp G is associated with the, jack l). A\swill be observed, supervisory lamp signals e2 and e3 are provided andassociated with the operators cord circuit. These supervisory signals.which are controlled b v suitable rela;y "'id by the switch-hooks atllal suli-stations.y enable the suliscribcrs lo signal the operator Fora discomwclhm. .\ll ol Vn current. both (hat which is employed fortalking and that which is employed lor sigz'- f nalin;r purposes, issupplied from a common battery or ccutralimal source oiI supply ll,

The line` lamp signals arc also controlled by suitable liml andcntotlwvlays` and h v the .said suitch-hoolts The jacks and plugs arcalso adapte/l. as will hereinafter said more fully appear, to ha vc acertain,

oi' control over the .said signals. ot my invention will, bonen-rl heunderstood by considering the manner in which the operator establishesconnection between the two lines.

Suppose, for example, that subscriber A desires to talk with;subscriberB. vIn such case, subscriber A removes his receiver a from the theswitch-hook a1, and in so doing closes aline circuit from the battery Hthrough the conductor 1, through the `Acoil r2 of the cut-0H relay,through the conductor 3 and the limb or line conductor 4, through thewinding 5 of the inductive connection between said receiver and the linecircuit, through the coi'tact 6 and the said switchhook a1, through thetransmitter 7 through the other limb or iine conductor 8, thence throughthe armature contact 9 and the stationary contact 10 of the cut-offrelay, through the-contact 11 and the armature 12 of the line relay,through the coil 13 ot' said line relay, through the conductor 14,through vthe stationary contact 15 and the armature contact 16 of thesaid cut-olf relay, thence through the conductor 17, and through theconductor' 18 to said battery.' The current flowing through this circuitis sufficient to energize ,therelay 13, and the relative resistances aresuch that this line relay is en# ergized and the circuit thereby openedbefore the current has time to energize the cut-off relay. The armature12 when atltracted by the magnet of the line relay 13,

opens kthe circuit of the coil 2, andat the same time closes a lo'calcircuit from the battery H through the ground or comnion connections 19and 20, through the line lamp signal F, through the contact point l21,through the armatureA 12, through the coil 13 of the line relay, thencethrough the conductor 14 and the contact 15, through the armaturecontact 16, and thence through the conductors 17 and 18 to said battery.Thus, as stated, the line relay opens the line circuit before thecurrent has time to energize the cut-ofi' relay, and in so doing closesthe local circuit of the line lamp and causes the latter to glow.' Theoperator observing this signal inserts the plug e in the jack C. Thiscloses a local circuit from the battery H through the ground or commonconnections 19 and 2 2, through thecoil of the supervisory relay 23,through the conductor 24, through the talking strand 25, through theplug sleeve 26, through the ring or thimble 27 of said jack, thencethrough the conductor 28 and Ithe coil 29 of the cut-off relay, andthrough the conductor 18 to said battery. The current flowing in thisderived circuit energizes the relay 23 and also the said cut-off relay.The relay 23 then pulls up its armature 30 and causes the same to engageKthe contact 31, thereby closing the normally open switch point in thecircuit of the supervisory lamp e2.- The energizing of the cut-oli relayattracts the armature 33,

ahommes and in so doing separates the contacts 15 and 16, therebyopening the local circuit of the relay 13 and the line lamp signal F. Inaddition, the energizing of the cut-off relay through this derivedcircuit causes the armature contact 9 to engage the stationary contact34, thereby closing the normally open. switch point in one side of thetalking circuit between the jack C and substation A.

It will also be observed that this energizing of the cut-off relayseparates thel contacts i 9 and 10. The closing of the contacts 9 and-34 not only establishes the continuity of the talking circuit, but alsocloses a line circuit including the battery and including both of thecoils 2 and 29. In this way the cut-off relay is fully energized andkeeps its armature in the proper .position during conversation betweenthe subscribers. The operator then presses 'her listening key e4, so asto bridge her talking set I across the cord circuit. She then converseswith the oil.

vcalling subscriber and learns the number of the desired connection.After this, she can then insert the calling plug e1L in the jack D. Thisact on the part'of the operator establishes a derived circuit from thebattery H through the ground or common connections 19 and 22, throughthe supervisory relay 35, through the conductor 36,*through the contact37 and the ringing key e, thence through the-talking strand 38, throughthe plug or thimble 40 of jack D, thence through I the conductor 41,through the coil 42 of the cut-olf relay L associated with the calledsubscribers line, and through the conductor 43 to said battery.l Thisenergizes the said cut-oil relay, causing it to attract-its arma ture44, and to thereby open a switch point;

in the derived local circuit of the lamp G and the' liiie relay 45. Inthis way the operator places the line signal apparatus in such conditionthat subscriber B can answer the call without causing the lamp G toglow. The current flowing through thisv circuit causes the relay 35 toattract its armature and thereby close a localcircuit from the battery Hthrough the ground or common connections 19 and 22, through the armature46 and the contact 47, through the super- 115 visory lamp c3, throughthe contact 48 and the armature 49, and through the conductor 50 to saidbattery. The current flowing through this local circuit is sufficient tolight the said lamp e3. Except possibly with the exception ofthe briefinterval in which the Voperator is projecting ringing current on to thecalled subscribers line for the purpose of ringing the bell atsub-station B, this laiiip c3 continues to glow until the sub- 125 57and 5o, through the relay 42 can be maintained in its energizedcondition during this projection of ringing current on to the calledsubscribers line, by simply providing the generator bridge 5l with aground tap 52 containing an inipedance coil Vvlith this ar 1angeinentthe pressing of the said ringing key completes a circuit from thebattery ll through the ground or connnon connections 1f) and 5l, throughthe said impedance coil 52E and the conductors 52 and 5l, through thecontact 55, Jthrough the said ringing key, through the talking strand35, tlnrough the plug sleeve 39 and the ring or thiinble -l-O ot thejack.n thence through the coiuluctor -ll and the coil 42 ot the eut-ott'relay, and thence through the conductor lf3 to said battery. In this waythe pressing ot, the ringing key establishes a temporary derived circuitfor maintaining the cut-ott relay in an energized condition, so as tokeep the contacts 5G and 57, through which the'ringing current inustpass in order to be oi' use, in a closed condition. The current from thegenerator ,l rings theI bell l) at sub-station B. This bell* ispreferably in series with 'the condenser 1. which latter stops the tlowof battery current, but at the samevtiine permits the passage ot' thealternating current troni the generator. At this juncture it will alsobe Seen 'that the hell at is arranged in series with a condenser (z3 atsub-station A. The Subscriber at sub-station B responds by re` movinghis receiver b2 from the switch hook b1, thereby closing a line circuitfrom the hattery'lil through' the connections Alf) and 22, through thesupervisory relay 59. through the conductor 5S), through the con` tactGO and the listening key et, through the conductor 61 and the contact(S2. through the ringing key c5 and the talking strand (3?, through theplug tip G-l and the jack spring 65, through the conductor (Slt throughthe winding (i7 ot the inductive connection between the receiver b2 andthe line circuit. through the contact 68, through the switch hook bl,through the transmitter (Si). through the line conductor Tt), throughthe contacts coil l2 ot` the cut-ott' relay, and tlience through theconductor lil to said battery. lt will also be observed that the calledsubscriber' in answvering` the call completes a line circuit includingthe coil 7l ot the cut-ott' relay associated with this line.` ln otherAwords. the relays 55% and 7l are placed in parallel. The energizing otthe relay 5S cpens the normally closed switch point composed of thearmature 4l; and the contact 4:7 in the local circuit ot the lamp u".thereby causing the latter to cease glowing. In this way the calledsubscriber in a nswcring the call restores the supervisory Isignal andthereby advises the operator that he has responded and is incommunication with i l l l cuits are open at the `ubfl the callingsubscriber. The through talkl juncture, it will be seen that ing circuitthus established between the two subscribers includes, it will heobserved, the limbs of the two lines, the plug and jack contacts, andthe talking strands ort the cord circuit, the latter being preferablyprovided with condensers 72 and 73. During conversation current issupplied to this talking circuitV through the coils and 29 and 7l andl2, which in this way lact. as resistance to regulate the currentsupply. Furthermore, as these coils are provided with cures, so thatthey may also act as cut-oltI relays, it will he seen that 'they havethe further t'uuction of acting as impedance or retard'..tio.n toprevent the passage ot' voice eiuren'ts The relays in the cord circuit,although bridged across the cord circuit` are ot' substantially highimpedance or retardation to prevent the passage through them ot' thevoice currents traversing the talking circuit.

When the subscribers have finished their conversation, and have hung uptheir receivers, the opening of the line circuits causes the lamps @2and c3 to glow. Suppose, for example, that subscriber A hangs up hisreceiver tirst. The opening ot' the line circuity leadingt'roni thissub-station opens the circuit of the supervisory relay 74., it beingobserved that during conversation this relay has remained energized`owing to itsbeing connected at such time in parallel with the coil Q.This relay 7l when deenergized completes a local circuit from thebattery H through the connections 19 and 2Q, through the armature T5 andthe contact TG, through the lamp c2, through the contact 3l and thearmature 30. and through tho conductor TT to said battery. This causeslthe lamp e2 to `glow and thereby give the signal t'or disconnection. lna similar inanncr the subscriber at substation l); in hanging up hisreeei ver opens the line circuit. dc ei'iergizes the relay 58. and thuscloses the previously described circuit. ot the lamp c3. The said lampthen responds to the [low o'll current and gives the signal fordisconnection at' this end ot the cord circuit. 'llhe operator. uponwithdrawing the plugs troni the jacks, opens thecircuits ot' the relays23E and 35. and thus restores the lauipsc'-` and r3. 'lhe withdra valot' the plugs` in thisI manner also. ot course. deliuergif/,es the coils:'29 and li ot the two cut-ott relays, allowing the latter toreestablish the normally open switch points iu the two line circuits. Italso lrestablishes the normally closed shunts around these two switchpoints, but ina`- uuu-h as the line circuitsA are open al the.sub-statitms. the (lt-energizing ol the cut-oli relays in this mannerdoes not cause the line lamps lo glow. This is duc. it will be seen. lothe 'tact that no battery current can flow through the relays l and i3when the ril- :ltliil *.X llllH the coilsll and 29, the contacts 15and'16, the armature 12 Mid the contact 11, and the contacts v1() and 9constitute normally'closed shunts around the normally' openswitch pointcomposed 5 of the contacts 9 and 34. This shunt, it will be seen, isthus not only controlled by the cut-ofi' relay K, but also, by the linerelay 13. .In this way the said line relay is adapted lto form part ofboth line and local circuits, and to automatically openthe-sub-Ascribers line circuit and simultaneously therewith close the circuit ofthe lamp F.'

Thus there 'is no current on the subscribers line when the operatorplugs-in and cuts the battery oft' from the line signal, andconsequently the operator can vanswer the call without producing anobjectionable noise in the receiver at sub-station A. In other words,the' arrangement tends to quiet the line in answering calls.V In alsimilar way thecoil 42 and thecoil45, contacts 78 and 79, the contacts80 and 81, and the contact 57 and the armature 82, constitute a normallyclosed shunt around the normally open switchpoint coin osed of thecontacts 56 andA 57. The coi of the line rela 45 is adapted to serve aspart of both line and ,v local circuits, and this relay is adapted, likef the relay 13, to automatically open the line 30 circuit andsimultaneously therewith close the local circuit of the lamp G when thesubscriber at sub-statioii B calls-iii. In other words, the line signalapparatus at this side of the circuit is substantially the same as theline signal apparatus allotted to the line leading from sub-station vA.

It will be seen that with my improved apparatus only two wires orconductors are necessary for each jack, and that only two strands arenecessary for the cord circuit, notwithstanding the fact that myimproved system is characterized by the mostapproved methods ofoperation. with respect to signaling and supervision, and also withrespect to current supply andthe manner in which the connections areestablished.

It is obvious thatl the resistaiices of t-he various relays can beadjusted or regulated to suit the conditions of any particular case, andcan be varied Within limits and to an extent which will not beinconsistent with their functions and mode of operation. It is alsoobvious that tlie feature of having the relays 18 and l5 more responsivethan the 55 coils 2 and 71 of the cut-oit relays, can be accomplished inany suitable manner.v For example, this can be done by a suitableadjustment or regulation of the resistances of the different coils, soas to have the coils 2 and 71 insure a more sluggish action orenergizing of the cut-off relays than that of the line relays. Again,the cutotf relays can'be given a tighter adjustment, or can be somechanically constructed that the line 65 relays will pull up and breakthe circuits of the coils 2 and 71 before the cut-olf relays can becomeenergized. In other words, any suitable expedient can be employed forenabling the line relays torespond quickly and 'in such manner as toopen the circuits of the coils'2 and 71 and close the circuits of thelain s F and Gr before the cut-oil relays can become sutlicientlyenergized to attract their armatures and open the switch points whichthey'themselves control in the circuits of the line relays.

Other advantages will be obvious to those skilled in the art.

' What I claim as my invention is 1. A telephone system comprising asubscribers line, a subseribers switchfor opning and closing` the linecircuit, a central source of current, a line relay provided withnormally closed and normally open contacts, a line lamp signal, andsuitable'circuitconneetions whereby the coil of said relay and its saidnormally closed switch contacts are included in a line circuit when thesubscriber calls-in,xand whereby the said lamp signal and normally opencontacts are then 9e included in a closed local circuit by theenergizing of the said relay.

2. A telephone system comprisingy a subscribers line, a line 'relay andmeans for energizing it, said relay lbeing provided with normally closedcontacts through which the coil of saidreay is adapted to be initiallyenergized ,and a local energizin circuit for said relay adapted to beclosed y the energizing'of the same. y

3. A telephone system comprising a subscribers line, suitablesub-station apparatus, and vsuitable switchboard apparatus, the latterapparatus including a line relay p adapted when energized to open theline ci'r- 105 cuit by which it is energized. 4 f

scribers line, suitable sub-station apparatus, and suitable switchboardapparatus, the latter apparatus including a" .line relay 110 havingnormally closed contacts adapted to serve as part of the initialenergizing circuit of said rela and a local energizing circuit for saidre ay adaptednto be closed by y the energizing of the same.

5. A telephone system comprising a subscribers line, suitablesub-station apparatus, and switchboard apparatus, thelatter apparat-usincluding a line relay and a cut-off relay, said relays having normallyclosed contacts connected normally in s'eries with the coils of saidrelays, and also -in series with said line.

6. A telephone system comprising a subscribers line, suitablesub-station apparatus, and switchboard apparatus, the latter apparatusincluding line -and cut-ott` relays,A said eut-ott' relay having a coiladapted to serve as part of .the initial energizing cir y 'cuit of saidline relay and a localA energizing 1.30

telephone system comprising a subcircuit torsaid relay adapted to beclosed by the energizing of the same.

'l'. n. telephone system comprising a subscribers line,suitable-,substation apparatus, and switchboard ati'paratus, the latterapparatus including linehanld cut-ott relays, said relajzsliaringnormally closed contacts,

and said cut-eil' relay having a coil adapted with said contacts toconstitute a part of the initial energizing circuit of said line relay.

S. A teleplionesystein comprising a sub? scribers line,suitable/su'us'tation apparatus, a spring jack, a relay, a battery forfurnishing current to energize said relay, an operators cord circuitproyidedwth a plug adapted for insertion in said jack, a bridge adaptedto be connected with opposite sides oi said cord circuit, said bridgeincluding a generator, suitable circuit connections, and an impedancecoil connected `between said bridge and ground, said impedance coilbeing adapted to insure an energizing circuit for said relay during thetime the said gen erator is connected with the said circuit.

9. A telephone system comprising rsubscriberslines, suitable sub-stationapparatus for each line, a two-way spring jack connected with cach line,a normally open switchpoiiit in one side ot each line, a line relay anda cut-ottrelay for each line, line lamp signals adapted to be controlledby said line relays, eacliy oit said relays being provided with normallyclosed contacts, ncrmally closed shunts around said normally open switchpoints, each shunt including" normally closed contacts and coils of saidrelays, an operators tWo-Way cord circuit provided with plugs adaptedfor insertion in said jacks, a pair of relays bridged across one end ofthe cord circuit, a supervisory lamp adapted to.be conjointly controlledby said pair of relays, another pair of reT lays bridged across theother end of the cord' circuit, a second supervisory lamp adapted to beconjointly controlled by said second pair of relays, one relay of eachpair being adapted to be controlled by one of said plugs and jacks, theother relay of each pair being adapted to be conjointly controlled byone of said plugs and jacks and means at a sub-station, and suitablecircuit connections and means tor supplying current.

10. in a telephone system, tlie combination o'a subscribcrs line relay,a subscribers line, a normally open line circuit for initiallyenergizing said relay, said relay being adapted to open said circuit as.soon as energized, and a local energizing circuit tor said relay adaptedto be closed as soon as the saine is energized.

ll. ln telephone system, the combination with a telephone line, ot aline relay therefor, a line signal, a cutoff relay for the line, saidcut-oit relay having-a pair of conall necessary tacts normally in serieswith the line relay, said contacts being in series with `the line relayand the line signal during the display of the signal, the actuation oftlie cut-ott relay being adapted to open said contacts.

l2. In a telephone system, the combination with a telephone line, of aline relay and a source of current normally bridged between the limbs ofthe telephone line at the central olicc, a line signah the actuation ofsaid line relay being adapted to sever said bridge and to place saidline signal and said Yline relay in a local circuit with said source,

and a cut-ott relay adapted to be actuated to sever said local circuitand to replace said source in a. bridge between the line conduc-` tors.

13. In a telephone system, the combina` tion with a telephone line, ot asource of cur. rent and a line relay normally bridged be tween the limbsof said line at the central oice, a local energizing circuit for saidline relay and a cut-oil` relay adapted, when actuated, to sever thelocal energizing circuit for said line relay.

14. In a telephone exchange system, the combination of a supervisorysignal, a pair of relays conjointly controlling said signal, a localenergizing circuit for one of said relays, a line signal, a second pairof relays conjointly controlling the said line signal, and local andline circuits .each controlled by the relays of said second pair.

l5. In a telephone exchange system, the combination of a supervisorysignal, a pair ot relays conjointly controlling said signal, a localenergizing circuit for one of said relays, a line signal, a second pairof relays conjointly cont-rolling the said line, signal, local and linecircuits each controlled by the relays of said second pair, and anenergizing circuit common to a relay ot eacli pair.

16. ln a telephone exchange system, tlic combination ot a` supervisorysignal, a pair of relays conjointly controlling said signal, a localenergizing circuit for one ot said rc lays, a line signal, a second pairof relays conjointly controlling the said line signal,

local and line circuit-s each controlled by the relays 'of said secondpair, and an energizing circuit common to a relay of said energizingcircuit being local.

17. In a telephone exchange system, the combination ot a supervisorysignal. a of relays conjointly controlling seid si a local energizingcircuit for one ot s relays, a line signal, a second ,lair ot .c eachcontrolling the said lino si and line circuits conjointly 'contro relaysof said second pair. an ener cuit common to a relay ot eac'o telephoneline included in salu circuit. l l 18. In a telephone syst-ein, mi.,.'i. line, a line relay, a jack for .sain luie, a cuteacli pair,

SOY

off relay for opening the circuit. of the line relay and closing atalking connection between the jack and the line, one side of the linebeing permanently connected with the jack, a cord circuit having a pairot' supervisory relays bridged'between the talking strands thereof, asupervisory signal controlled byl said supervisor-y relays, and a localcil-cuit 'for'energizing the cut-oli relay .in series with one of saidsupervisory relays .the line, a' cord circuit hayinga pair, ofsupervisory,` relays' bridged ,between the talk! strandsf'thereof, meansfor supplying current to' the line Vfor talking purposes, a supervisorysignal controlled ,by said super visory relays, and a circuitl forenergizing the cut-0E relay' in series with the jack and one offsai'dv'superyisory relays, the energiz-v ing lof the cut olf'relay serving todisconnect the linel relay from the line.

20.-In1a telephone system, a subscribers line, a jack provided with acontact perinan'ently connected withone side of said line, a. linerelay, and a cut-olf relay provided with means for denergizing said linerelay and closing a talking connection between the jack and the Iother.side of said line, the energizing of the cut 0H relay serving todisconnectthe line relay from the line.

21'. In a telephone system, a subscribers fline, a jack having onecontact thereof permanently connected with one side of the line, a linerelay, a circuit for energizing the line relay, and a cut-ofi' relayprovided with nieansfor simultaneously opening said circuit andestablishing a talking connection between the'jack and the other side ofsaid line, the energizing of the cut off relay Iserving to disconnectIthe line relay from the line.

22. In a telephone syste'rn, gis'ubs'cribes'` line, a line relay, asource of current, said relay being normally connected between one sideof the line and one pole of the source of current, a line circuitincluding the relay and source of current in series, a vlocal circuitfor said relay, and a cut-off relay provided with means for opening saidcircuit at a point between said line relay and the pole of the source ofcurrent to which it isA normally connected. l

23. In a telephone system, a subscribers line, a line relay therefor, asource of talking and' operating current, a hne circiut m- '24. Inl atelephone s ste'm,la11 subscribers or,za.,soll1rce` of talkv line, -aline-,relay there ing and Loperating current, afgackfhaving one contactthereof permanently. connected with one side of the line, anelect-romagnet, a line circuit including the line relay in series withthe said source of current, means operated by said electromagnet foropening ysaid circuit at a point betweenjthe line rela.

and the pole of said source of current wit cuit for said relay, andmeans operated by said electromagnet for closin a talking con- .vnection between the jack van the other slde of the line.

25.v In a telephone system, a llne, a relay controlling the continuityof said line and having a winding included in a normally closed batterybridge across said line at ther exchange of central station.l

Signed by me at Chicago, Cook county,

Illinois, this 18th day of July, 1903." .i

HENRYv P. CLAUSEN. Witnesses:

A. F. DURAND, WM. A. HARDERS.

80 which it is normally connected, a local cirf

